BD 500 – year 1927
Manufacturer: Machine factory, Breitfeld-Danek, Prague X, Czechoslovakia
In the mid twenties, when American and English products predominated on the Czechoslovak motorcycle market and domestic production was fragmented and remained at the level of small-commodity handicraft production, The aviation department of the Breitfeld-Danek Machine Factory is not too overloaded with work, received an order from the then Ministry of National Defense to make a trial series of motorcycles with a cylinder capacity 500 cm3. The development of the new motorcycle was entrusted to the well-known motorcycle designer Jarosław F.. Koch. Koch already had some of his own, completed projects. Among them, the model stood out 350, with an overhead valve (OHC), with a king roller, manufactured under the JFK brand. The camshaft in this vehicle also powered the magneto, located above the cylinder head.
In the new motorcycle, Koch used the experience gained in the construction of previous models, and therefore the prototype of the vehicle was built - under his guidance - in a record time of three months. Motorcycle, which received the unofficial name Bedar turned out to be a successful construction, the company obtained further orders and several series of 500 copies were produced.
The characteristic features of BD motorcycles were a modern four-stroke engine with a displacement 499 cm3, reaching at 4000 rpm power 11 kW (15 KM). The valves were controlled by two overhead camshafts (2 x OHC). The three-speed gearbox locked with the engine could be easily removed from the power unit. The wheel mounting solution was noteworthy, which were mutually exchangeable, the rear wheel was removed without removing the chain. Motorcycle, equipped with a double tubular frame, had a mass 178 kg and developed maximum speed 105 km/h.
W 1929 In the year, the factory was incorporated into the Ćeskomoravske Strojirny concern (with a department for the production of famous Prague cars). BD motorcycle 500 however, it was still produced after a few minor refinements (new lubrication system, improved fuel tank and headlight), under the name of Praga BD 500.
Due to poor profitability, w 1935 In the year, the production of motorcycles in this concern was discontinued.